Elliptically polarizing plate and organic light-emitting device

ABSTRACT

Provided is an elliptically polarizing plate and an organic light-emitting device. The elliptically polarizing plate of the present application can provide an elliptically polarizing plate with superior visibility having excellent reflection characteristics and color characteristics on the side as well as the front, and an organic light-emitting device comprising the same.

CROSS-REFERENCE TO RELATED APPLICATION(S)

The present application is a National Stage Application of InternationalApplication No. PCT/KR2019/004622 filed on Apr. 15, 2019, which claimsthe benefit of priority based on Korea Patent Application No.10-2018-0044317 filed on Apr. 17, 2018, the disclosures of which areincorporated herein by reference in its entirety.

FIELD

The present application relates to an elliptically polarizing plate andan organic light-emitting device.

BACKGROUND ART

Recently, there has been a demand for weight reduction and thinning ofmonitors, televisions, and the like, and organic light-emitting devices(OLEDs) have been attracting attention in response to this demand. Anorganic light-emitting device is a self-luminescent display deviceemitting light by itself, which requires no separate backlight, so thatthe thickness can be reduced, and is advantageous to realize a flexibledisplay device.

On the other hand, an organic light-emitting device can reflect externallight by the metal electrode and the metal wiring formed on the organiclight-emitting display panel, whereby visibility and a contrast ratiocan be lowered due to the reflected external light, therebydeteriorating the display quality. A circularly polarizing plate can beattached to one side of the organic light-emitting display panel, as inPatent Document 1 (Korean Laid-Open Patent Publication No.2009-0122138), to reduce leakage of the reflected external light to theoutside.

However, the currently developed circularly polarizing plate has strongviewing angle dependence, and thus an antireflection performancedeteriorates toward the side, so that there is a problem that thevisibility is lowered.

SUMMARY

The present application provides an elliptically polarizing plate withsuperior visibility having excellent reflection characteristics andcolor characteristics on the side as well as the front, and an organiclight-emitting device comprising the same.

The present application relates to an elliptically polarizing plate.FIG. 1 illustrates a structure of an elliptically polarizing plateaccording to an exemplary embodiment of the present application. Asillustrated in FIG. 1, the elliptically polarizing plate can comprise,sequentially, a linear polarizer (50), a first retardation film (10), asecond retardation film (20), a third retardation film (30) and a fourthretardation film (40).

In this specification, the polarizer means an element exhibitingselective transmission and absorption characteristics with respect toincident light. For example, the polarizer can transmit light thatvibrates in any one direction from incident light that vibrates invarious directions, and absorb light that vibrates in the otherdirections.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exemplary illustration of a cross-section of anelliptically polarizing plate according to one example of the presentapplication.

FIG. 2 is an exemplary illustration of a cross-section of an organiclight-emitting device according to one example of the presentapplication.

DETAILED DESCRIPTION

In this specification, a linear polarizer means a polarizer in which theselectively transmitting light is a linearly polarized light thatvibrates in any one direction and the selectively absorbing light is alinearly polarized light that vibrates in a direction orthogonal to thevibration direction of the linearly polarized light.

As the linear polarizer, for example, a polarizer in which iodine isdyed on a polymer stretched film such as a PVA stretched film or aguest-host polarizer in which a liquid crystal polymerized in anoriented state is used as a host and an anisotropic dye arrangeddepending on the orientation of the liquid crystal is used as a guestcan be used, without being limited thereto.

According to one example of the present application, a PVA stretchedfilm can be used as the linear polarizer. The transmittance orpolarization degree of the linear polarizer can be appropriatelyadjusted in consideration of the objective of the present application.For example, the transmittance of the linear polarizer can be from 42.5%to 55%, and the polarization degree can be from 65% to 99.9997%.

In this specification, when terms such as vertical, horizontal,orthogonal or parallel are used while defining an angle, it meanssubstantially vertical, horizontal, orthogonal, or parallel to theextent that the desired effect is not impaired, which includes, forexample, an error that takes a production error or a deviation(variation), and the like, into account. For example, each case of theforegoing can include an error within about ±15 degrees, an error withinabout ±10 degrees or an error within about ±5 degrees.

In this specification, the retardation film is an optically anisotropicelement, which means an element capable of converting incident polarizedlight by controlling birefringence. While describing an x-axis, y-axisand z-axis of the retardation film herein, unless otherwise specified,the x-axis means a direction parallel to an in-plane slow axis of theretardation film, the y-axis means a direction parallel to an in-planefast axis of the retardation film, and the z-axis means a thicknessdirection of the retardation film. The x-axis and y-axis can beorthogonal to each other in the plane. An optical axis of theretardation film herein, unless otherwise specified, it means a slowaxis. When the retardation film comprises rod-shaped liquid crystalmolecules, the slow axis means the long axis direction of the rod shape,and when it comprises disc-shaped liquid crystal molecules, the slowaxis means the normal direction of the disc shape.

In this specification, the Nz value of the retardation film iscalculated by the following Equation 1:

Nz=(nx−nz)/(nx−ny).  <Equation 1>

In this specification, the retardation film satisfying the followingExpression 1 can be a so-called +C plate.

In this specification, the retardation film satisfying the followingExpression 2 can be a so-called +B plate.

In this specification, the retardation film satisfying the followingExpression 3 can be a so-called −B plate.

In this specification, the retardation film satisfying the followingExpression 4 can be a so-called +A plate.

nx=ny<nz.  <Expression 1>

ny<nx≠nz.  <Expression 2>

nx>ny>nz.  <Expression 3>

nx>ny=nz.  <Expression 4>

In this specification, the thickness direction retardation value (Rth)of the retardation film is calculated by the following Equation 2.

In this specification, the in-plane retardation value (Rin) of theretardation film is calculated by the following Equation 3.

Rth=(nz−ny)×d.  <Equation 2>

Rin=(nx−ny)×d.  <Equation 3>

In Equations 1 to 3 and Expressions 1 to 4, nx, ny and nz are refractiveindexes in x-axis, y-axis and z-axis directions as defined above,respectively, and d is the thickness of the retardation film.

In this specification, the reverse wavelength dispersion characteristicmeans a characteristic satisfying the following Equation 4, the normalwavelength dispersion characteristic means a characteristic satisfyingthe following Equation 5, and the flat wavelength dispersioncharacteristic means a characteristic satisfying the following Equation6:

R(450)/R(550)<R(650)/R(550);  <Equation 4>

R(450)/R(550)>R(650)/R(550);  <Equation 5>

R(450)/R(550)=R(650)/R(550).  <Equation 6>

The refractive index of the retardation film as described herein, meansa refractive index for light of a wavelength of about 550 nm, unlessotherwise specified. Here, R(λ) means an in-plane retardation value orthickness direction retardation value for light with λ nm.

The present application can realize an elliptically polarizing platehaving superior visibilityon the side as well as the front bycontrolling the optical properties of the first retardation film, thesecond retardation film, the third retardation film and the fourthretardation film. As one example, the elliptically polarizing plate ofthe present application can have a color difference maximum value ofless than 2.8, less than 2.7, less than 2.6, less than 2.5, or less than2.4 at a tilt angle of 40 degrees and an azimuth angle of 45 degrees or135 degrees. In this specification, the color difference means how thecolor of the side differs from the color of the front when theelliptically polarizing plate has been applied to an organiclight-emitting display panel, which means a value ΔE*_(ab) in colorcharacteristic simulation evaluation of the examples described herein.

The first retardation film can be a +B plate in which the Nz value ofEquation 1 is less than 0 or a +C plate satisfying Expression 1. In thecase of the +C plate satisfying Expression 1, the value ofNz=(nx−nz)/(nx−ny) is not defined because nx=ny.

When the first retardation film is a +B plate, the Nz value can be,specifically, less than 0, −0.1 or less, −0.2 or less, −0.3 or less,−0.4 or less, or −0.5 or less. The lower limit of the Nz value can be,specifically, −50 or more, −40 or more, −30 or more, or −20 or more.When the Nz value of the first retardation film satisfies the aboverange, it exhibits excellent reflection characteristics and colorcharacteristics on the side as well as the front, whereby it can beadvantageous to realize an elliptically polarizing plate having superiorvisibility.

When the first retardation film is a +B plate, the in-plane retardationvalue for light with a wavelength of 550 nm can be 0 nm to 100 nm. Thein-plane retardation value can be, specifically, 1 nm or more, 2 nm ormore, 3 nm or more, 4 nm or more, or 5 nm or more, and can be 100 nm orless, 95 nm or less, 90 nm or less, 85 nm or less, or 80 nm or less.When the in-plane retardation value of the first retardation filmsatisfies the above range, it exhibits excellent reflectioncharacteristics and color characteristics on the side as well as thefront, whereby it can be advantageous to realize an ellipticallypolarizing plate having superior visibility.

When the first retardation film is a +B plate, the thickness directionretardation value can be 10 nm to 250 nm. The thickness directionretardation value can be, specifically, 10 nm or more, 20 nm or more, 30nm or more, or 35 nm or more, and can be 250 nm or less, 240 nm or less,230 nm or less, or 225 nm or less. When the thickness directionretardation value of the first retardation film satisfies the aboverange, it exhibits excellent reflection characteristics and colorcharacteristics on the side as well as the front, whereby it can beadvantageous to realize an elliptically polarizing plate having superiorvisibility.

When the first retardation film is a +B plate, the in-plane slow axiscan be perpendicular or parallel to the absorption axis of the linearpolarizer. As a result, it exhibits excellent reflection characteristicsand color characteristics on the side as well as the front, whereby itcan be advantageous to realize an elliptically polarizing plate havingsuperior visibility.

When the first retardation film is a +C plate, the thickness directionretardation value can be 5 nm to 430 nm. The thickness directionretardation value can be, specifically, 5 nm or more, 10 nm or more, 20nm or more, or 30 nm or more, and can be 430 nm or less, 420 nm or less,410 nm or less, or 400 nm or less. When the thickness directionretardation value of the first retardation film satisfies the aboverange, it exhibits excellent reflection characteristics and colorcharacteristics on the side as well as the front, whereby it can beadvantageous to realize an elliptically polarizing plate having superiorvisibility.

In the present application, first to third examples can be implementeddepending on the first retardation film. According to the first exampleof the present application, the first retardation film can be a +Cplate. According to the second example of the present application, thefirst retardation film can be a +B plate, and the slow axis can beparallel to the absorption axis of the linear polarizer. According tothe third example of the present application, the first retardation filmcan be a +B plate, and the slow axis can be perpendicular to theabsorption axis of the linear polarizer.

The second retardation film can be a −B plate having an Nz value of morethan 1. The Nz value can be, specifically, 1.15 or more, or 1.2 or more.The upper limit of the Nz value can be, specifically, 20 or less, 15 orless, 10 or less, 8 or less, or 6 or less. When the Nz value of thesecond retardation film satisfies the above range, it exhibits excellentreflection characteristics and color characteristics on the side as wellas the front, whereby it can be advantageous to realize an ellipticallypolarizing plate having superior visibility.

The in-plane retardation value of the second retardation film for lighthaving a wavelength of 550 nm can be 5 nm to 130 nm. The in-planeretardation value can be, specifically, 5 nm or more, 10 nm or more, 15nm or more, 20 nm or more, or 25 nm or more, and can be 130 nm or less,125 nm or less, 120 nm or less, 115 nm or less, or 110 nm or less. Whenthe in-plane retardation value of the second retardation film satisfiesthe above range, it exhibits excellent reflection characteristics andcolor characteristics on the side as well as the front, whereby it canbe advantageous to realize an elliptically polarizing plate havingsuperior visibility.

The thickness direction retardation value of the second retardation filmcan be −220 nm to −5 nm. The thickness direction retardation value canbe, specifically, −220 nm or more, −215 nm or more, or −213 nm or more,and can be −5 nm or less, −10 nm or less, −12 nm or less, or −14 nm orless. When the thickness direction retardation value of the secondretardation film satisfies the above range, it exhibits excellentreflection characteristics and color characteristics on the side as wellas the front, whereby it can be advantageous to realize an ellipticallypolarizing plate having superior visibility.

In the second retardation film, the in-plane slow axis can be parallelto the absorption axis of the linear polarizer. As a result, it exhibitsexcellent reflection characteristics and color characteristics on theside as well as the front, whereby it can be advantageous to realize anelliptically polarizing plate having superior visibility.

The sum of the thickness direction retardation value of the firstretardation film and the thickness direction retardation value of thesecond retardation film can be −20 nm to 200 nm. The sum can be,specifically, −20 nm or more, −15 nm or more, −10 nm or more, or −5 nmor more, and can be 200 nm or less, 195 nm or less, 190 nm or less, or187.5 nm or less. As a result, it exhibits excellent reflectioncharacteristics and color characteristics on the side as well as thefront, whereby it can be advantageous to realize an ellipticallypolarizing plate having superior visibility.

The third retardation film can have an Nz value of 0.8 to 1.2. The thirdretardation film can be a +B plate, a −B plate, or a +A plate. When theNz value of the third retardation film is 1.0, it is a +A plate; whenthe value is 0.8 or more to less than 1.0, it is a +B plate close to the+A plate; and when the value is more than 1.0 to less than 1.2, it is a−B plate close to the +A plate.

The third retardation film can have a quarter-wave phase retardationcharacteristic. In this specification, the term “n-wave phaseretardation characteristic” can mean a characteristic that the incidentlight can be phase-delayed by n times the wavelength of the incidentlight within at least a part of the wavelength range. Therefore, thequarter-wave phase retardation characteristic can mean a characteristicthat the incident light can be phase-delayed by a quarter times thewavelength of the incident light within at least a part of thewavelength range.

The in-plane retardation value of the third retardation film for lighthaving a wavelength of 550 nm can be 120 nm to 160 nm, specifically, 130nm to 150 nm. When the in-plane retardation value of the thirdretardation film satisfies the above range, it exhibits excellentreflection characteristics and color characteristics on the side as wellas the front, whereby it can be advantageous to realize an ellipticallypolarizing plate having superior visibility.

The in-plane slow axis of the third retardation film can form about 40degrees to about 50 degrees, about 43 degrees to about 47 degrees,specifically, about 45 degrees with the absorption axis of the linearpolarizer. As a result, it exhibits excellent reflection characteristicsand color characteristics on the side as well as the front, whereby itcan be advantageous to realize an elliptically polarizing plate havingsuperior visibility.

The fourth retardation film can be a +C plate or a +B plate. When thefourth retardation film is a +B plate, the Nz value can be −4.0 or less.When the Nz value of the fourth retardation film is −4.0 or less, it canbe a +B plate close to the +C plate. The lower limit of the Nz value inthe fourth retardation film can be, for example, −3000 or more. When thefourth retardation film is a +C plate, the value of Nz=(nx−nz)/(nx−ny)may not be defined because nx=ny.

When the fourth retardation film is a +B plate, the in-plane slow axiscan form an angle of about 40 degrees to 50 degrees, about 43 degrees to47 degrees, specifically, about 45 degrees with the light absorptionaxis of the linear polarizer. As a result, it exhibits excellentreflection characteristics and color characteristics on the side as wellas the front, whereby it can be advantageous to realize an ellipticallypolarizing plate having superior visibility.

The fourth retardation film can have a thickness direction retardationvalue of 0 nm or more. Specifically, the thickness direction retardationvalue of the fourth retardation film can be 0 nm to 300 nm. Morespecifically, the thickness direction retardation value of the fourthretardation film can be 0 nm or more, 10 nm or more, 20 nm or more, 30nm or more, 50 nm or more, or 65 nm or more, and can be 300 nm or less,250 nm or less, 200 nm or less, 150 nm or less, 100 nm or less, or 75 nmor less. When the thickness direction retardation value of the fourthretardation film satisfies the above range, it exhibits excellentreflection characteristics and color characteristics on the side as wellas the front, whereby it can be advantageous to realize an ellipticallypolarizing plate having superior visibility.

The first to fourth retardation films can each have a reverse wavelengthdispersion characteristic, a normal wavelength dispersion characteristicor a flat wavelength dispersion characteristic. In one example, thefirst retardation film can have an R (450)/R (550) value of 0.6 to 1.3,or an Rth (450)/Rth (550) value of 0.6 to 1.3. In one example, thesecond retardation film can have an R (450)/R (550) value of 0.6 to 1.3.In one example, the third retardation film can have an R (450)/R (550)value of 0.60 to 1.0, specifically, 0.6 to 0.99 or 0.6 to 0.92. The R(650)/R (550) value of the third retardation film can be 1.01 to 1.19,1.05 to 1.15, or 1.09 to 1.11, while having a value greater than the R(450)/R (550) value. In one example, the fourth retardation film canhave an Rth (450)/Rth (550) value of 0.6 to 1.3. Here, R (2) means anin-plane retardation value of a retardation film for light with λ nm,and Rth (2) means a thickness direction retardation value of aretardation film for light with λ nm. When the wavelength dispersioncharacteristics of the first to fourth retardation films are within theabove ranges, it exhibits excellent reflection characteristics and colorcharacteristics on the side as well as the front, whereby it can beadvantageous to realize an elliptically polarizing plate having superiorvisibility.

The first to fourth retardation films can each be a polymer film or aliquid crystal film. As the polymer film, a film comprising polyolefinsuch as PC (polycarbonate), norbomene resin, PVA (poly(vinyl alcohol)),PS (polystyrene), PMMA (poly(methyl methacrylate) and PP(polypropylene), Par (poly(arylate)), PA (polyamide), PET (poly(ethyleneterephthalate)) or PS (polysulfone), and the like can be used. Thepolymer film can be stretched or shrunk under appropriate conditions toimpart birefringence and used as the first to fourth retardation films.The liquid crystal film can comprise liquid crystal molecules in a stateof being oriented and polymerized. The liquid crystal molecule can be apolymerizable liquid crystal molecule. In this specification, thepolymerizable liquid crystal molecule can mean a molecule containing amoiety capable of exhibiting liquid crystallinity, such as a mesogenskeleton, and containing at least one polymerizable functional group.Also, the fact to comprise polymerizable liquid crystal molecules in apolymerized form can mean a state in which the liquid crystal moleculesare polymerized to form a skeleton such as a main chain or side chain ofthe liquid crystal polymer in the liquid crystal film.

The thicknesses of the first to fourth retardation films can be eachappropriately adjusted in consideration of the object of the presentapplication. For example, the thicknesses of the first to fourthretardation films can be each independently 0.1 μm to 100 μm.

The elliptically polarizing plate can further comprise a surfacetreatment layer. The surface treatment layer can be exemplified by anantireflection layer or the like. The surface treatment layer can bedisposed on the outer side of the linear polarizer, for example, on theopposite side where the first retardation film is disposed. As theantireflection layer, a laminate of two or more layers having differentrefractive indexes or the like can be used, without being limitedthereto.

In the elliptically polarizing plate, the first retardation film, thesecond retardation film, the third retardation film, and the fourthretardation film to the linear polarizer can be attached to each otherthrough a pressure-sensitive adhesive or an adhesive, or can belaminated to each other by direct coating. An optical transparentpressure-sensitive adhesive or adhesive can be used as thepressure-sensitive adhesive or adhesive.

The elliptically polarizing plate of the present application can preventthe reflection of external light, thereby improving the visibility ofthe organic light-emitting device. While incident unpolarized light(hereinafter referred to as “external light”) incident from the outsidepasses through a linear polarizer, one polarized orthogonal component,that is, a first polarized orthogonal component, of two polarizedorthogonal components can be only transmitted and the polarized lightcan be changed to circularly polarized light while passing through thethird retardation film. While the circularly polarized light isreflected from a display panel of an organic light-emitting displaydevice comprising a substrate, an electrode, and the like, therotational direction of the circularly polarized light is changed andthe circularly polarized light is converted to the other polarizedorthogonal component of two polarized orthogonal components, that is, asecond polarized orthogonal component while passing through the thirdretardation film again. The second polarized orthogonal component doesnot pass through the linear polarizer and thus does not emit light tothe outside, so that it can have an effect of preventing reflection ofexternal light.

The elliptically polarizing plate of the present application can alsoeffectively prevent the reflection of external light incident from,particularly, the side, thereby improving the lateral visibility of theorganic light-emitting device. For example, the elliptically polarizingplate of the present application can also effectively prevent thereflection of external light incident from the side through viewingangle polarization compensation principle.

The elliptically polarizing plate of the present application can beapplied to an organic light-emitting device. FIG. 2 is a cross-sectionalillustration of an organic light-emitting device to which theelliptically polarizing plate of the present application is appliedaccording to an exemplary embodiment. Referring to FIG. 2, the organiclight-emitting device comprises an organic light-emitting display panel(200) and an elliptically polarizing plate (100) positioned on one sideof the organic light-emitting display panel (200). The fourthretardation film (40) of the elliptically polarizing plate can bedisposed adjacent to the organic light-emitting display panel (200) ascompared with the linear polarizer (50).

The organic light-emitting display panel can comprise a base substrate,a lower electrode, an organic light-emitting layer, an upper electrodeand a sealing substrate, and the like. One of the lower electrode andthe upper electrode can be an anode and the other can be a cathode. Theanode is an electrode into which holes are injected, which can be madeof a conductive material having a high work function, and the cathode isan electrode into which electrons are injected, which can be made of aconductive material having a low work function. At least one of thelower electrode and the upper electrode can be made of a transparentconductive material such that the emitted light can come out to theoutside, and can be, for example, ITO or IZO. The organic light-emittinglayer can comprise an organic material capable of emitting light when avoltage has been applied to the lower electrode and the upper electrode.

Additional layers can be further included between the lower electrodeand the organic light-emitting layer and between the upper electrode andthe organic light-emitting layer. The additional layer can include ahole transporting layer, a hole injecting layer, an electron injectinglayer and an electron transporting layer for balancing electrons andholes, but is not limited thereto. The sealing substrate can be made ofglass, metal, and/or a polymer, and can seal the lower electrode, theorganic light-emitting layer, and the upper electrode to preventmoisture and/or oxygen from being introduced from the outside.

The elliptically polarizing plate can be disposed on the side where thelight comes out from the organic light-emitting display panel. Forexample, in the case of a bottom emission structure in which light isemitted toward the base substrate, it can be disposed outside the basesubstrate, and in the case of atop emission structure in which light isemitted toward the sealing substrate, it can be disposed outside thesealing substrate. The elliptically polarizing plate can improve displaycharacteristics of the organic light-emitting device by preventingexternal light from being reflected by the reflective layer made ofmetal such as electrodes and wiring of the organic light-emittingdisplay panel and from coming out of the organic light-emitting device.In addition, since the elliptically polarizing plate can exhibit anantireflection effect on the side as well as the front, as describedabove, the lateral visibility can be improved.

The present application can provide an elliptically polarizing platewith superior visibility having excellent reflection characteristics andcolor characteristics on the side as well as the front, and an organiclight-emitting device comprising the same.

Hereinafter, the present application will be described in detail by wayof examples according to the present application and comparativeexamples not complying with the present application, but the scope ofthe present application is not limited by the following examples.

Evaluation Example 1 Evaluation of Color Characteristic Simulation

For Examples and Comparative Examples, the color characteristics(Techwiz 1D plus, Sanayi System Co., Ltd.) in the front and side weresimulated and evaluated. The color differences (ΔE^(*) _(ab), dE) aredefined by the following Equation 7:

ΔE _(ab)*=√{square root over ((L ₁ *−L ₂*)²+(a ₁ *−a ₂*)²+(b ₁ *−b₂*)²)}.  Equation 7>

In Equation 7 above, (L*₁, a*₁, b*₁) mean reflection color values at thefront (tilt angle 0°, azimuth angle 0°), and (L*₂, a*₂, b*₂) meanreflection color values at the side (specific tilt angle and azimuthangle). The dE max values were recorded based on the maximum value of dEvalues at a tilt angle of 40 degrees and an azimuth angle of 45 degreesor 135 degrees. The color difference value (dE value) shows how much theside color differs from the front color. If the ΔE*_(ab) value is 2.3,it can be regarded as JND (just noticeable difference), and if theΔE*_(ab) value is less than 2.4, it can be said that the performanceclose to JND is realized.

Example 1

An elliptically polarizing plate comprising, sequentially, a polarizer,a first retardation film, a second retardation film, a third retardationfilm and a fourth retardation film was prepared, and the ellipticallypolarizing plate was disposed so that the fourth retardation film wasadjacent to an OLED panel.

The polarizer was a linear polarizer having single transmittance (Ts) of42.5%, and the OLED panel was a Galaxy S6 smartphone. The firstretardation film was a +C plate and the second retardation film was a −Bplate. The third retardation film had an R (450)/R (550) value of 0.86and an Rin value of 140 nm, where its slow axis formed an angle of 45degrees with the absorption axis of the polarizer. The fourthretardation film was a +C plate having an Rth value of 60 nm. Here, theRin means an in-plane retardation value of a retardation film for lighthaving a wavelength of 550 nm, and the Rth means a thickness directionretardation value of a retardation film for light having a wavelength of550 nm.

When the Nz values of the second retardation film were 1.2, 3.0 and 6.0,Table 1, Table 2 and Table 3 show the optical properties of the firstand second retardation films exhibiting dE Max values of less than 2.4at a tilt angle of 40 degrees inclination angle, respectively.

TABLE 1 First and First Second Retardation Retardation dE Max SecondRetardation Film Film Films @ a tilt Nz Rin Rth Rth Rth total angle of40° 1.2 70 −14 34 20 2.34 1.2 80 −16 36 20 2.14 1.2 80 −16 46 30 2.201.2 90 −18 38 20 2.06 1.2 90 −18 48 30 1.93 1.2 90 −18 58 40 2.04 1.2 90−18 68 50 2.35 1.2 100 −20 40 20 2.12 1.2 100 −20 50 30 1.85 1.2 100 −2060 40 1.79 1.2 100 −20 70 50 1.86 1.2 100 −20 80 60 2.15 1.2 110 −22 4220 2.30 1.2 110 −22 52 30 2.06 1.2 110 −22 62 40 1.94 1.2 110 −22 72 501.94 1.2 110 −22 82 60 2.05 1.2 110 −22 92 70 2.23

TABLE 2 First and First Second Retardation Retardation dE Max SecondRetardation Film Film Films @ a tilt Nz Rin Rth Rth Rth total angle of40° 3 35 −70 90 20 2.38 3 35 −70 95 25 2.35 3 40 −80 105 25 2.26 3 40−80 110 30 2.19 3 40 −80 115 35 2.27 3 45 −90 115 25 2.39 3 45 −90 12030 2.19 3 45 −90 125 35 2.05 3 45 −90 130 40 2.07 3 45 −90 135 45 2.18 345 −90 140 50 2.34 3 50 −100 135 35 2.23 3 50 −100 140 40 2.05 3 50 −100145 45 1.94 3 50 −100 150 50 1.97 3 50 −100 155 55 2.07 3 50 −100 160 602.23 3 55 −110 155 45 2.27 3 55 −110 160 50 2.10 3 55 −110 165 55 1.95 355 −110 170 60 1.90 3 55 −110 175 65 1.98 3 55 −110 180 70 2.12 3 55−110 185 75 2.30 3 60 −120 185 65 2.30 3 60 −120 190 70 2.19 3 60 −120195 75 2.11 3 60 −120 200 80 2.04 3 60 −120 205 85 2.19 3 60 −120 210 902.37

TABLE 3 First and First Second Retardation Retardation dE Max SecondRetardation Film Film Films @ a tilt Nz Rin Rth Rth Rth total angle of40° 6 25 −125 167.5 42.5 2.37 6 25 −125 170 45 2.31 6 25 −125 172.5 47.52.31 6 25 −125 175 50 2.34 6 25 −125 177.5 52.5 2.37 6 27.5 −137.5 187.550 2.34 6 27.5 −137.5 190 52.5 2.27 6 27.5 −137.5 192.5 55 2.22 6 27.5−137.5 195 57.5 2.22 6 27.5 −137.5 197.5 60 2.23 6 27.5 −137.5 200 62.52.26 6 27.5 −137.5 202.5 65 2.30 6 27.5 −137.5 205 67.5 2.36 6 30 −150207.5 57.5 2.38 6 30 −150 210 60 2.30 6 30 −150 212.5 62.5 2.22 6 30−150 215 65 2.15 6 30 −150 217.5 67.5 2.13 6 30 −150 220 70 2.13 6 30−150 222.5 72.5 2.15 6 30 −150 225 75 2.17 6 30 −150 227.5 77.5 2.21 630 −150 230 80 2.26 6 30 −150 232.5 82.5 2.32 6 30 −150 235 85 2.39 632.5 −162.5 232.5 70 2.34 6 32.5 −162.5 235 72.5 2.26 6 32.5 −162.5237.5 75 2.18 6 32.5 −162.5 240 77.5 2.10 6 32.5 −162.5 242.5 80 2.07 632.5 −162.5 245 82.5 2.06 6 32.5 −162.5 247.5 85 2.07 6 32.5 −162.5 25087.5 2.08 6 32.5 −162.5 252.5 90 2.10 6 32.5 −162.5 255 92.5 2.14 6 32.5−162.5 257.5 95 2.19 6 32.5 −162.5 260 97.5 2.25 6 32.5 −162.5 262.5 1002.31 6 32.5 −162.5 265 102.5 2.39 6 35 −175 260 85 2.33 6 35 −175 262.587.5 2.25 6 35 −175 265 90 2.17 6 35 −175 267.5 92.5 2.10 6 35 −175 27095 2.03 6 35 −175 272.5 97.5 2.02 6 35 −175 275 100 2.02 6 35 −175 277.5102.5 2.02 6 35 −175 280 105 2.04 6 35 −175 282.5 107.5 2.07 6 35 −175285 110 2.10 6 35 −175 287.5 112.5 2.15 6 35 −175 290 115 2.20 6 35 −175292.5 117.5 2.27 6 35 −175 295 120 2.34 6 37.5 −187.5 290 102.5 2.38 637.5 −187.5 292.5 105 2.31 6 37.5 −187.5 295 107.5 2.24 6 37.5 −187.5297.5 110 2.17 6 37.5 −187.5 300 112.5 2.10 6 37.5 −187.5 302.5 115 2.046 37.5 −187.5 305 117.5 2.00 6 37.5 −187.5 307.5 120 2.00 6 37.5 −187.5310 122.5 2.01 6 37.5 −187.5 312.5 125 2.03 6 37.5 −187.5 315 127.5 2.066 37.5 −187.5 317.5 130 2.10 6 37.5 −187.5 320 132.5 2.14 6 37.5 −187.5322.5 135 2.19 6 37.5 −187.5 325 137.5 2.25 6 37.5 −187.5 327.5 140 2.326 37.5 −187.5 330 142.5 2.39 6 40 −200 330 130 2.35 6 40 −200 332.5132.5 2.29 6 40 −200 335 135 2.23 6 40 −200 337.5 137.5 2.18 6 40 −200340 140 2.13 6 40 −200 342.5 142.5 2.08 6 40 −200 345 145 2.04 6 40 −200347.5 147.5 2.06 6 40 −200 350 150 2.09 6 40 −200 352.5 152.5 2.13 6 40−200 355 155 2.17 6 40 −200 357.5 157.5 2.22 6 40 −200 360 160 2.27 6 40−200 362.5 162.5 2.33 6 40 −200 365 165 2.40 6 42.5 −212.5 380 167.52.38 6 42.5 −212.5 382.5 170 2.34 6 42.5 −212.5 385 172.5 2.31 6 42.5−212.5 387.5 175 2.27 6 42.5 −212.5 390 177.5 2.24 6 42.5 −212.5 392.5180 2.23 6 42.5 −212.5 395 182.5 2.28 6 42.5 −212.5 397.5 185 2.32 642.5 −212.5 400 187.5 2.38

Example 2

The same structure as that of Example 1 was set up, except that thefirst retardation film and the second retardation film were each changedas follows.

The first retardation film was a +B plate, where its slow axis isparallel to the absorption axis of the polarizer. The second retardationfilm was a −B plate, where its slow axis is parallel to the absorptionaxis of the polarizer.

When the Nz values of the second retardation film were 1.2 and 6.0,respectively, Table 4 and Table 5 show the optical properties of thefirst and second retardation films exhibiting dE Max values of less than2.4 at a tilt angle of 40 degrees, respectively.

TABLE 4 First and Second Second First Retardation dE Max RetardationFilm Retardation Film Films @ a tilt Nz Rin Rth Nz Rin Rth Rth totalangle of 40° 1.2 100 −20 −1.5 20.0 50 30 2.39 1.2 100 −20 −1.5 22.0 5535 2.34 1.2 100 −20 −1.5 24.0 60 40 2.34 1.2 100 −20 −1.5 26.0 65 452.37 1.2 100 −20 −2 16.7 50 30 2.33 1.2 100 −20 −2 18.3 55 35 2.27 1.2100 −20 −2 20.0 60 40 2.25 1.2 100 −20 −2 21.7 65 45 2.27 1.2 100 −20 −223.3 70 50 2.33 1.2 100 −20 −2.5 12.9 45 25 2.39 1.2 100 −20 −2.5 14.350 30 2.29 1.2 100 −20 −2.5 15.7 55 35 2.22 1.2 100 −20 −2.5 17.1 60 402.21 1.2 100 −20 −2.5 18.6 65 45 2.21 1.2 100 −20 −2.5 20.0 70 50 2.261.2 100 −20 −2.5 21.4 75 55 2.35 1.2 100 −20 −3 11.3 45 25 2.36 1.2 100−20 −3 12.5 50 30 2.26 1.2 100 −20 −3 13.8 55 35 2.19 1.2 100 −20 −315.0 60 40 2.20 1.2 100 −20 −3 16.3 65 45 2.20 1.2 100 −20 −3 17.5 70 502.21 1.2 100 −20 −3 18.8 75 55 2.29 1.2 100 −20 −3.5 10.0 45 25 2.34 1.2100 −20 −3.5 11.1 50 30 2.24 1.2 100 −20 −3.5 12.2 55 35 2.18 1.2 100−20 −3.5 13.3 60 40 2.19 1.2 100 −20 −3.5 14.4 65 45 2.19 1.2 100 −20−3.5 15.6 70 50 2.20 1.2 100 −20 −3.5 16.7 75 55 2.26 1.2 100 −20 −3.517.8 80 60 2.37 1.2 100 −20 −4 9.0 45 25 2.33 1.2 100 −20 −4 10.0 50 302.22 1.2 100 −20 −4 11.0 55 35 2.18 1.2 100 −20 −4 12.0 60 40 2.18 1.2100 −20 −4 13.0 65 45 2.19 1.2 100 −20 −4 14.0 70 50 2.19 1.2 100 −20 −415.0 75 55 2.24 1.2 100 −20 −4.5 8.2 45 25 2.32 1.2 100 −20 −4.5 9.1 5030 2.21 1.2 100 −20 −4.5 10.0 55 35 2.17 1.2 100 −20 −4.5 10.9 60 402.18 1.2 100 −20 −4.5 11.8 65 45 2.18 1.2 100 −20 −4.5 12.7 70 50 2.191.2 100 −20 −4.5 13.6 75 55 2.26 1.2 100 −20 −5 7.5 45 25 2.31 1.2 100−20 −5 8.3 50 30 2.20 1.2 100 −20 −5 9.2 55 35 2.17 1.2 100 −20 −5 10.060 40 2.17 1.2 100 −20 −5 10.8 65 45 2.18 1.2 100 −20 −5 11.7 70 50 2.181.2 100 −20 −5 12.5 75 55 2.28

TABLE 5 First and Second Second First Retardation dE Max RetardationFilm Retardation Film Films @ a tilt Nz Rin Rth Nz Rin Rth Rth totalangle of 40° 6 37.5 −187.5 −9 20.3 202.5 15 2.37 6 37.5 −187.5 −10 17.5192.5 5 2.39 6 37.5 −187.5 −10 18.0 197.5 10 2.27 6 37.5 −187.5 −10 18.4202.5 15 2.27 6 37.5 −187.5 −11 16.0 192.5 5 2.28 6 37.5 −187.5 −11 16.5197.5 10 2.17 6 37.5 −187.5 −11 16.9 202.5 15 2.25 6 37.5 −187.5 −1214.4 187.5 0 2.38 6 37.5 −187.5 −12 14.8 192.5 5 2.19 6 37.5 −187.5 −1215.2 197.5 10 2.08 6 37.5 −187.5 −12 15.6 202.5 15 2.23 6 37.5 −187.5−13 13.4 187.5 0 2.31 6 37.5 −187.5 −13 13.8 192.5 5 2.12 6 37.5 −187.5−13 14.1 197.5 10 2.02 6 37.5 −187.5 −13 14.5 202.5 15 2.22 6 37.5−187.5 −14 12.5 187.5 0 2.25 6 37.5 −187.5 −14 12.8 192.5 5 2.06 6 37.5−187.5 −14 13.2 197.5 10 2.01 6 37.5 −187.5 −14 13.5 202.5 15 2.22 637.5 −187.5 −15 11.7 187.5 0 2.20 6 37.5 −187.5 −15 12.0 192.5 5 2.01 637.5 −187.5 −15 12.3 197.5 10 2.00 6 37.5 −187.5 −15 12.7 202.5 15 2.216 37.5 −187.5 −16 11.0 187.5 0 2.15 6 37.5 −187.5 −16 11.3 192.5 5 1.976 37.5 −187.5 −16 11.6 197.5 10 2.00 6 37.5 −187.5 −16 11.9 202.5 152.21 6 37.5 −187.5 −17 10.1 182.5 −5 2.38 6 37.5 −187.5 −17 10.4 187.5 02.12 6 37.5 −187.5 −17 10.7 192.5 5 1.94 6 37.5 −187.5 −17 11.0 197.5 101.99 6 37.5 −187.5 −17 11.3 202.5 15 2.21 6 37.5 −187.5 −18 9.6 182.5 −52.35 6 37.5 −187.5 −18 9.9 187.5 0 2.09 6 37.5 −187.5 −18 10.1 192.5 51.91 6 37.5 −187.5 −18 10.4 197.5 10 1.99 6 37.5 −187.5 −18 10.7 202.515 2.21 6 37.5 −187.5 −19 9.1 182.5 −5 2.32 6 37.5 −187.5 −19 9.4 187.50 2.06 6 37.5 −187.5 −19 9.6 192.5 5 1.91 6 37.5 −187.5 −19 9.9 197.5 101.98 6 37.5 −187.5 −19 10.1 202.5 15 2.21 6 37.5 −187.5 −20 8.7 182.5 −52.30 6 37.5 −187.5 −20 8.9 187.5 0 2.04 6 37.5 −187.5 −20 9.2 192.5 51.90 6 37.5 −187.5 −20 9.4 197.5 10 1.98 6 37.5 −187.5 −20 9.6 202.5 152.21

Example 3

The same structure as that of Example 1 was set up, except that thefirst retardation film and the second retardation film were each changedas follows.

The first retardation film was a +B plate, where its slow axis isperpendicular to the absorption axis of the polarizer. The secondretardation film was a −B plate, where its slow axis is parallel to theabsorption axis of the polarizer.

When the Nz values of the second retardation film were 1.2 and 6.0,Table 6 and Table 7 show optical properties of the first and secondretardation films exhibiting dE Max values of less than 2.4 at a tiltangle of 40 degrees, respectively.

TABLE 6 First and Second Second First Retardation dE Max RetardationFilm Retardation Film Films @ a tilt Nz Rin Rth Nz Rin Rth Rth totalangle of 40° 1.2 100 −20 −0.5 60.0 90 70 2.38 1.2 100 −20 −0.5 63.3 9575 2.36 1.2 100 −20 −0.5 66.7 100 80 2.36 1.2 100 −20 −0.5 70.0 105 852.37 1.2 100 −20 −0.5 73.3 110 90 2.39 1.2 100 −20 −1 32.5 65 45 2.341.2 100 −20 −1 35.0 70 50 2.25 1.2 100 −20 −1 37.5 75 55 2.21 1.2 100−20 −1 40.0 80 60 2.20 1.2 100 −20 −1 42.5 85 65 2.21 1.2 100 −20 −145.0 90 70 2.25 1.2 100 −20 −1 47.5 95 75 2.32 1.2 100 −20 −1.5 22.0 5535 2.40 1.2 100 −20 −1.5 24.0 60 40 2.28 1.2 100 −20 −1.5 26.0 65 452.18 1.2 100 −20 −1.5 28.0 70 50 2.14 1.2 100 −20 −1.5 30.0 75 55 2.141.2 100 −20 −1.5 32.0 80 60 2.17 1.2 100 −20 −1.5 34.0 85 65 2.24 1.2100 −20 −1.5 36.0 90 70 2.35 1.2 100 −20 −2 18.3 55 35 2.30 1.2 100 −20−2 20.0 60 40 2.19 1.2 100 −20 −2 21.7 65 45 2.11 1.2 100 −20 −2 23.3 7050 2.10 1.2 100 −20 −2 25.0 75 55 2.14 1.2 100 −20 −2 26.7 80 60 2.211.2 100 −20 −2 28.3 85 65 2.32 1.2 100 −20 −2.5 14.3 50 30 2.36 1.2 100−20 −2.5 15.7 55 35 2.23 1.2 100 −20 −2.5 17.1 60 40 2.13 1.2 100 −20−2.5 18.6 65 45 2.08 1.2 100 −20 −2.5 20.0 70 50 2.10 1.2 100 −20 −2.521.4 75 55 2.15 1.2 100 −20 −2.5 22.9 80 60 2.26 1.2 100 −20 −2.5 24.385 65 2.40 1.2 100 −20 −3 12.5 50 30 2.32 1.2 100 −20 −3 13.8 55 35 2.191.2 100 −20 −3 15.0 60 40 2.10 1.2 100 −20 −3 16.3 65 45 2.07 1.2 100−20 −3 17.5 70 50 2.10 1.2 100 −20 −3 18.8 75 55 2.18 1.2 100 −20 −320.0 80 60 2.30 1.2 100 −20 −3.5 11.1 50 30 2.28 1.2 100 −20 −3.5 12.255 35 2.16 1.2 100 −20 −3.5 13.3 60 40 2.08 1.2 100 −20 −3.5 14.4 65 452.06 1.2 100 −20 −3.5 15.6 70 50 2.11 1.2 100 −20 −3.5 16.7 75 55 2.201.2 100 −20 −3.5 17.8 80 60 2.34 1.2 100 −20 −4 10.0 50 30 2.26 1.2 100−20 −4 11.0 55 35 2.14 1.2 100 −20 −4 12.0 60 40 2.06 1.2 100 −20 −413.0 65 45 2.06 1.2 100 −20 −4 14.0 70 50 2.12 1.2 100 −20 −4 15.0 75 552.23 1.2 100 −20 −4 16.0 80 60 2.38 1.2 100 −20 −4.5 8.2 45 25 2.38 1.2100 −20 −4.5 9.1 50 30 2.24 1.2 100 −20 −4.5 10.0 55 35 2.13 1.2 100 −20−4.5 10.9 60 40 2.06 1.2 100 −20 −4.5 11.8 65 45 2.06 1.2 100 −20 −4.512.7 70 50 2.13 1.2 100 −20 −4.5 13.6 75 55 2.25 1.2 100 −20 −5 7.5 4525 2.37 1.2 100 −20 −5 8.3 50 30 2.22 1.2 100 −20 −5 9.2 55 35 2.11 1.2100 −20 −5 10.0 60 40 2.07 1.2 100 −20 −5 10.8 65 45 2.07 1.2 100 −20 −511.7 70 50 2.14 1.2 100 −20 −5 12.5 75 55 2.26

TABLE 7 First and Second Second First Retardation dE Max RetardationFilm Retardation Film Films @ a tilt Nz Rin Rth Nz Rin Rth Rth totalangle of 40° 6 37.5 −187.5 −7 25.9 207.5 20 2.33 6 37.5 −187.5 −7 26.6212.5 25 2.36 6 37.5 −187.5 −8 22.5 202.5 15 2.28 6 37.5 −187.5 −8 23.1207.5 20 2.23 6 37.5 −187.5 −8 23.6 212.5 25 2.30 6 37.5 −187.5 −9 19.8197.5 10 2.32 6 37.5 −187.5 −9 20.3 202.5 15 2.18 6 37.5 −187.5 −9 20.8207.5 20 2.17 6 37.5 −187.5 −9 21.3 212.5 25 2.29 6 37.5 −187.5 −10 18.0197.5 10 2.22 6 37.5 −187.5 −10 18.4 202.5 15 2.12 6 37.5 −187.5 −1018.9 207.5 20 2.14 6 37.5 −187.5 −10 19.3 212.5 25 2.29 6 37.5 −187.5−11 16.0 192.5 5 2.35 6 37.5 −187.5 −11 16.5 197.5 10 2.15 6 37.5 −187.5−11 16.9 202.5 15 2.07 6 37.5 −187.5 −11 17.3 207.5 20 2.13 6 37.5−187.5 −11 17.7 212.5 25 2.31 6 37.5 −187.5 −12 14.8 192.5 5 2.28 6 37.5−187.5 −12 15.2 197.5 10 2.10 6 37.5 −187.5 −12 15.6 202.5 15 2.04 637.5 −187.5 −12 16.0 207.5 20 2.12 6 37.5 −187.5 −12 16.3 212.5 25 2.346 37.5 −187.5 −13 13.8 192.5 5 2.22 6 37.5 −187.5 −13 14.1 197.5 10 2.066 37.5 −187.5 −13 14.5 202.5 15 2.02 6 37.5 −187.5 −13 14.8 207.5 202.13 6 37.5 −187.5 −13 15.2 212.5 25 2.36 6 37.5 −187.5 −14 12.8 192.5 52.18 6 37.5 −187.5 −14 13.2 197.5 10 2.02 6 37.5 −187.5 −14 13.5 202.515 2.01 6 37.5 −187.5 −14 13.8 207.5 20 2.14 6 37.5 −187.5 −14 14.2212.5 25 2.39 6 37.5 −187.5 −15 11.7 187.5 0 2.38 6 37.5 −187.5 −15 12.0192.5 5 2.14 6 37.5 −187.5 −15 12.3 197.5 10 2.00 6 37.5 −187.5 −15 12.7202.5 15 2.00 6 37.5 −187.5 −15 13.0 207.5 20 2.15 6 37.5 −187.5 −1611.0 187.5 0 2.34 6 37.5 −187.5 −16 11.3 192.5 5 2.10 6 37.5 −187.5 −1611.6 197.5 10 1.98 6 37.5 −187.5 −16 11.9 202.5 15 2.00 6 37.5 −187.5−16 12.2 207.5 20 2.16 6 37.5 −187.5 −17 10.4 187.5 0 2.31 6 37.5 −187.5−17 10.7 192.5 5 2.08 6 37.5 −187.5 −17 11.0 197.5 10 1.96 6 37.5 −187.5−17 11.3 202.5 15 2.00 6 37.5 −187.5 −17 11.5 207.5 20 2.17 6 37.5−187.5 −18 9.9 187.5 0 2.28 6 37.5 −187.5 −18 10.1 192.5 5 2.05 6 37.5−187.5 −18 10.4 197.5 10 1.95 6 37.5 −187.5 −18 10.7 202.5 15 2.00 637.5 −187.5 −18 10.9 207.5 20 2.19 6 37.5 −187.5 −19 9.4 187.5 0 2.25 637.5 −187.5 −19 9.6 192.5 5 2.03 6 37.5 −187.5 −19 9.9 197.5 10 1.94 637.5 −187.5 −19 10.1 202.5 15 2.00 6 37.5 −187.5 −19 10.4 207.5 20 2.206 37.5 −187.5 −20 8.9 187.5 0 2.23 6 37.5 −187.5 −20 9.2 192.5 5 2.02 637.5 −187.5 −20 9.4 197.5 10 1.93 6 37.5 −187.5 −20 9.6 202.5 15 2.00 637.5 −187.5 −20 9.9 207.5 20 2.21

Comparative Example 1

The same structure as that of Example 1 was set up, except that theelliptically polarizing plate comprising the polarizer, the thirdretardation film and the fourth retardation film sequentially was setwithout comprising the first retardation film and the second retardationfilm. The dE max value of Comparative Example 1 was 2.8.

REFERENCE NUMERALS USED HEREIN

-   -   10: first retardation film    -   20: second retardation film    -   30: third retardation film    -   40: fourth retardation film    -   50: linear polarizer    -   100: elliptically polarizing plate    -   200: organic light-emitting display panel

1. An elliptically polarizing plate comprising, sequentially, a linearpolarizer, a first retardation film, a second retardation film, a thirdretardation film and a fourth retardation film, wherein the firstretardation film is a +B plate having an Nz value of less than 0 inEquation 1, or a +C plate satisfying Expression 1:Nz=(nx−nz)/(nx−ny),  <Equation 1>nx=ny<nz,  <Expression 1> wherein the second retardation film is a −Bplate having an Nz value of more than 1 in Equation 1, wherein the thirdretardation film has an Nz value of 0.8 to 1.2 in Equation 1, andwherein an in-plane slow axis of the third retardation film forms anangle of 43 degrees to 47 degrees with an absorption axis of the linearpolarizer, wherein the fourth retardation film is a +B plate having anNz value of −4.0 or less in Equation 1, or a +C plate satisfyingExpression 1, and wherein a sum of a thickness direction retardationvalue of the first retardation film and a thickness directionretardation value of the second retardation film is in a range of −20 nmto 200 nm and a thickness direction retardation value (Rth) iscalculated according to Equation 2:Rth=(nz−ny)×d,  <Equation 2> wherein, nx, ny and nz are refractiveindexes of the first to fourth retardation films in x-axis, y-axis andz-axis directions, respectively, and wherein the x-axis is a directionparallel to an in-plane slow axis of the first to fourth retardationfilms, the y-axis is a direction parallel to an in-plane fast axis ofthe first to fourth retardation films, the z-axis is a thicknessdirection of the first to fourth retardation films, and d is a thicknessof the first to fourth retardation films.
 2. The elliptically polarizingplate according to claim 1, wherein the first retardation film is a +Bplate having an Nz value of −0.5 or less.
 3. The elliptically polarizingplate according to claim 1, wherein the first retardation film is a +Bplate having an in-plane retardation value of 0 nm to 100 nm for lighthaving a wavelength of 550 nm.
 4. The elliptically polarizing plateaccording to claim 1, wherein the first retardation film is a +B plateand the thickness direction retardation value of the first retardationfilm is from 10 nm to 250 nm.
 5. The elliptically polarizing plateaccording to claim 1, wherein the first retardation film is a +B plate,and wherein the in-plane slow axis of the first retardation film isperpendicular or parallel to the absorption axis of the linearpolarizer.
 6. The elliptically polarizing plate according to claim 1,wherein the first retardation film is a +C plate the thickness directionretardation value of the first retardation film is from 5 nm to 430 nm.7. The elliptically polarizing plate according to claim 1, wherein thefirst retardation film has an R (450)/R (550) value of 0.6 to 1.3 or anRth (450)/Rth (550) value of 0.6 to 1.3, wherein R (λ) is an in-planeretardation value of the first retardation film for light having awavelength of λ nm, and Rth (λ) is the thickness direction retardationvalue of the first retardation film for light having a wavelength of λnm.
 8. The elliptically polarizing plate according to claim 1, whereinthe Nz value of the second retardation film is from 1.2 to
 6. 9. Theelliptically polarizing plate according to claim 1, wherein the secondretardation film has an in-plane retardation value of 5 nm to 130 nm forlight having a wavelength of 550 nm.
 10. The elliptically polarizingplate according to claim 1, wherein the thickness direction retardationvalue of the second retardation film is from −220 nm to −5 nm.
 11. Theelliptically polarizing plate according to claim 1, wherein the in-planeslow axis of the second retardation film is parallel to the absorptionaxis of the linear polarizer.
 12. The elliptically polarizing plateaccording to claim 1, wherein the second retardation film has an R(450)/R (550) value of 0.6 to 1.3, wherein R (λ) is an in-planeretardation value of the second retardation film for light having awavelength of λ nm.
 13. The elliptically polarizing plate according toclaim 1, wherein the third retardation film has an in-plane retardationvalue of 130 nm to 150 nm for light having a wavelength of 550 nm. 14.The elliptically polarizing plate according to claim 1, wherein thethird retardation film has an R (450)/R (550) value of 0.6 to 1.0,wherein R (λ) is an in-plane retardation value of the third retardationfilm for light having a wavelength of λ nm.
 15. The ellipticallypolarizing plate according to claim 1, wherein the thickness directionretardation value of the fourth retardation film is from 0 nm to 300 nm.16. The elliptically polarizing plate according to claim 1, wherein thefourth retardation film has an Rth (450)/Rth (550) value of 0.6 to 1.3,wherein Rth (λ) is the thickness direction retardation value of thefourth retardation film for light having a wavelength of λ nm.
 17. Anorganic light-emitting device comprising the elliptically polarizingplate of claim 1 and an organic light-emitting display panel.
 18. Theorganic light-emitting device according to claim 17, wherein the fourthretardation film of the elliptically polarizing plate is disposedadjacent to the organic light-emitting display panel.